Production of color photographic images



April ,1 A. FRQHLICH ErAL- I 2,373,821 PRODUCTION OF coLoR PHOTOGRAPHIJEC IMAGES Filed Feb. 17. 1942 f DENSITY INVENTORS ALFRED fiwHu'cH AND,

ATTORNEY-5 Patented Apr, 117,

GES

Alfred. Friihlich and Wilhelm Schneider, Dessau, Germany, assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application February 17, 1942,'Se'rial No. 431,272 In Germany October 19, 1940 IZ CIaims. (Cl. 95-6) The present invention relates to the produc-' .tion of color photographic .images and in particular of images obtained by color forming development. II

In the production of color photographicimages it is known to use in the photographic emulsion I layer 'or the developer dyestuff formers which yield dyestuif images by reaction with the oxidation products of the developing substance in the development of the latent silver image. For,

processes of; producing color images by means of a multi-layer material ltis ofimportance to ad just the color tones of the single partial dyestui! images so that they fulflll' the theoretical requirements of the subtractive tri-color process as' completely as possible. This requirement must especially be satisfied for the negative- Y positive process which requires the use of 'dyestufls having-particular spectral properties. Itis of the greatest importance for this" process that the blue dyestuil's transmit the rays' in the blue and green regions of the spectrum in a relatively large amount. .Bluddyestufls having this prop-. .erty have already been proposed. There are, for instance, used condensable phenols and naphthols which contain halogens as substituents- These halogen substituted products, however,

have the disadvantage that their solubility is very low compared with that of the non-substitutednaphthols so that it is sometimes practically im- I possible as, for instance, with pentabromonaphthol to obtain asumciently high concentration of dyestuflf formers inthe developer. Moreover, it-has been suggested to use phenols with nitro en'ous G-membered rings iusedon as, for'instance, hydroxyquinolines'instead of naphthols. However, it has been 'found that the color tone of the dyestuifs produced with these hydroxy quinolines is hardlydiilerent from the analogous dyestuffs derived from naphthol so that it is generally immaterial. for practical purposes whether a-naphthols or hydroxyquinolines areemplyed.

Itis furthermore known that three rings condensed together as, for instance, l-hydroxyanthrac ene yield, blue-green dyestuffs having avery I green color tone. These compoundahowver, are

not suitable, for'due ,to their extraordinary sensitivity to'air, developers containing these dyestuff formers become black .when exposed to air for a short time. I- lydroxyphenanthrenes would likeform greenish color tonesi These coinpounds-however, cannot be, used' because they cannot be prepared as yet on a technical scale.

35 -o o mr c The present invention is based on the observation that dyestufi formers yielding quinoneimine dyestuiis which exhibit an especially high absorption in the short wave infra-red and hence satisfy the requirements of the negative process as to the spectral properties of the dyestuffs to a large extentand are moreover suitable for the urposesof sound recording owing to the high absorption in the long wave red can be produced by using as dyestufi formers condensable aromatic "hydroxy compounds containing in theirmolecule a 5 -membered heterocyclic nucleus. I From the halogenated phenols and naphthols and the o-hydrox'yphenylbenzal compounds pro-- posed as components for the blue-green the dyestuif formers of the present'invention are distinguished in that they can additionally be substitut ed with great ease .owing to their constitution.

Thus they can without diiiiculty be substituted 2o by radicals which are especially favorable for photographic purposes as, for instance, nondiflusing radicals and groupsrenderi'ng the components soluble indiluted alkalies. ,Owing to the I easy introduction of several substituents it is also I possible to'influence the color tone in any desired manner. I The heterocyclic nucleus may be a free sub- "stituent as, ,for instance, the 5-membered ring in the condensation product from u-hydroxynaphthoic acid and nitroaminobenzthia'zole corre- I spending with the followingformula 1-hydroxy-2-naphthoyl-5'-nitro-2-amino benz 40 thiazole) and in the product obtained by condensing u -hydroxynaphthoic acid with o-am'inophenol and heating the reaction product to split oil water and having the following formula:

II I II l C/ND (l-hydroxynaphthalene 2.2 benzoxazole) and in the component obtained by heating the con- I den sation product from a-hydroxynaphthoic acid and o-phenylenediamine to split off water and having the following formula:

I Ono/ND (1 hydroxynaphthalene 2.2 benzimidazole). The heterocyclic nucleus may also directly be fused on the phenol or naphthol capable of coupling as, for instance, in hydroxynaphthylamino- I phenylthiazole sulionic acid of the following formula:

This compound and the homologues thereof are prepared in known manner as, for instance, ac-

' dyestufi former thus obtained possesses good cording to the process described in the German Patent 165,126.

The preferred compounds. according to the present invention are salts of phenols having joined thereto in ortho position to the phenolic hydroxyl group a radical such as a benzthiazole, a benzoxazole or a benzimidaaole, the carbon atom between the heteroatoms of the flve-membered ring of such heterocyclic radical being linked to the phenol through a nuclear carbon to carbon linkage and said salt having linked thereto a radical rendering, the salt fast to diflusion in gelatin. Examples of such compounds are given above.

Reference is made to the accompanying drawing the two figures of which show absorption curves 0! dyestui! formed from p-dimethylaminoaniline and dyestui! components of the presentinvention compared to absorption curves of dye stuffs from known dyestufl formers.

of the non-diflusing dyestui! formers may be cast to form single layers or worked up into multilayer materials containing the several emulsion layers on one or bothsides of the support and, if necessary, filter layers,intermediate layers or anti-halation layers.

Example Y 4 Into l-hydroxynaphthyl-5.6-3' sminophenylthiazole-2-sulfonic acid prepared in themanner described in German Patent 165,126 a radical preventing difl'usion may be introduccd'by reacting the dyestui! component with stearlc acid chloride or abietic acid chloride or perhydrodiphenylcarbonylic acid chloride. Owing to the presence of the suite group the non-diffusing solubility.

For the, production ofcolor images 3 g. of the dyestuilf former are dissolved in a mixture of 100 'cc. of water and 10 cc. oi n/1 sodium hydroxide solution. The obtained solution is then added to 300 cc.' of a silver halide gelatin emul sion whereupon the emulsion 'is usually cast to form a layer. The exposedlayer is treated with a color forming developer as, for instance, p-dimethylaminoaniline in soda-alkaline solution.

After fixing and removing the silver one obtains a green dyestufi image. 1

Instead of the sodium salt other solublesalts of the dyestufl former may be used, for instance, other alkali metal salts.

In Figure 1 the curve i represents the absorption curve of the dyestufl formed from 1-hydroxy- 2' naphthyl- 2 -benzimidazole -4'-sulfonic acid and p-dimethylaminoaniline and the curve 2 the absorption curve of the dyestufi formed from l'-hydroxy-2'-naphthyl-2-benzoxazole and p-dimethylaminoaniline. The curves 3 and 5 repre- .sent the absorption'ourves of the dyestuffs from the known dyestufl formers a'-naphthol and 2.4- dibromonaphthol respectively.

In Figure 2 the absorption curve I is that of the dyestufi from l-hydroxynaphthyl-5.6-3'*-aminophenylthiazole-2-sulfonic acid whereas the.

curves 2 and 3 are the absorption curves of the dyestufls from nz-naphthol and 2.4-dibromonaphthol respectively.

We claim:

1. In a process of producing color photographic images by color forming development, the improvement which comprises developing an exposed silver halide emulsion with an aromatic primary amino developer in the presence of a i water-soluble saltggof a phenol having joined thereto in ortho position to the phenolic hydroxyl group a radical selected from the class consisting of benzthiazole, benzoxazole' and benzimidazole radicals, the carbon atom between the hetero atoms of the flve-membered ring of said radical being linked to said phenol through a nuclear carbon to carbonlinkage.

- a soluble salt a: a phenol having joined thereto '2. In a process of producing color photographic.

images by color -forming development, the improvement which comprises developing an exposed photographic silver halide emulsion with an aromatic primary amino developer containing in ortho position to the phenolic hydroxyl group a radical selected from the classconsisting of benzthiazole, benzoxazole and benzimidazole-radicals, the carbon atom between the hetero atoms ot'the nve-membered ring of said radicalbei'ng linked to said phenol through a nuclear carbon 9 to carbon linkage. I

3. In a process of producing color photographic images by color forming development, the improvement which comprises developing with an aromatic primary-amino developer, a silver halide emulsion containing a soluble salt of a phenol having joined thereto in ortho position to the phenolic hydroxyl group a'radical selected from the class consisting of benzthiazole, benzoxazole andibensimidasole radicals, the carbon atom between-the hetero atoms of the flve-membered ring or said radical, being linked to said phenol through a nuclear carbon to carbon linkage.

4. A silver halide gelatin emulsion for color i'orming development containing a soluble salt of a phenol having joined thereto in ortho positionto the phenolic hydroxyl; groupa radical se- I lected from the class consisting of. benzthi'azole, benzoxazole and benzimidazole radicals, the carbon atom between thehetero atoms of the fivemembered ring of said radical being linked to" said phenol through a linkage.

5. A color forming developer comprising an aqueous solution containing an aromatic primary amino developing agent and a solubielsalt' of a nuclear carbon to carbon phenol having joined thereto in ortho position to the phenolic hydroxyl group aradical selected from the class consisting of benzthiazole, benzoxazole andbenzimidazole radicals, the carbon atom between the hetero atoms of the five-membered ring of said radical being linked to said phenol through a nuclear carbon to carbon linkage. I v g 6. In a process of producing'oolor photographic images by color-forming development, the-improvement which comprises developing an exposed silver halide emulsion with an aromatic primary amino developer in the presence of a salt of a phenol havingjoinedthereto in ortho position to the phenolic hydroxyl group aradicalselected from the class consisting of benzthiazoie, benzo'xazole and benzimidazole radicals, thecarbon atom between the hetero atoms of the flve membered ring of said radical being linked to said phenol through a nuclear carbon to-carbon linkage, said salt having joined thereto a radical rendering the salt fast to diflusion,

7.- A silver halide gelatin emulsion for colorforming development containing a salt of a,phe

nol having \joined thereto in ortho position to the phenolic .hydroxyl group a radical selected age, said salt containing a radical rendering the salt fast to difiuslon. Y 4 8. The process as defined in claim 1 wherein said phenol isanaphthol. p

9. The process as defined-in claim 2 wherein said phenol is a naphthol.

10. The composition as defined in claim 4 wherein said phenol is a naphthol.

11. A silver halide emulsion for color-forming development containing a'compound of the following constitution:

12. A silver halide emulsion for color forming development containing a compound of the 101- i lowing constitution ALFRED women. 7 wnmuvr scmmmma. 

